Combination fluid fuel burner



Feb. 11, 1958 BLACK I 2,822,864

COMBINATION FLUID F/UEL BURNER Y Filed Sept. 28, 1953 57 5 E 40 3 I a i i I 5 g: =gt= I 20 i2 0 ("/50 i i i i q 5? 50 5 i o /7 I so 23 /5 I I. 3g 756 i 44 i F IG. 1

INVENTOR JoZm T 19 Zack ATTORNEY United States Patent OT" 2,822,864 COMBINATIONv FLUID FUEL BURNER.

John T. Black, Rumson, N. J., assignor to The Babcock &. Wilcox Company, New York, N. Y., a corporation of New Jersey This invention relates to the construction and operatron of a combination fuel burner, capable of burning a plurality of fluid fuels simultaneously or separately.

There are many instances in which a by-product or waste gaseous fuel is available for intermittent use in small quantities along with a main supply of either another'gaseous fuel, or a liquid fuel. In the oilindustry, for example, gases of low heating value or gases which are available in generally small and usually intermittent or varying quantities, are burned in orv wastedto. the atmosphere because of a lack of suitable equipment whereby these gases can be burned satisfactorily and economically in heat utilization apparatus.

Accordingly, it is the main object of this invention to provide an improved construction and arrangement of a combination fluid fuel burner in heat utilization apparatus whereby a plurality of fuels of different heating values and burning characteristics may be burned efliciently, either separately or simultaneously.

A further object of the invention is to. provide a combination fuel burner for a plurality of fluid fuels whereby each of the fuels, while burning, aids in the ignition and burning of the other fuel or fuels.

For a better understanding of the invention principles, reference is made to the following description of a typical embodiment thereof as illustrated in the accompanying drawings.

Of the drawings:

Fig. 1 is a sectional elevation of a furnace wall incorporating a combination fuel burner constructed in accordance with my invention; and

Fig. 2' is a partial end elevation of the fuel burner shown in Fig. 1.

In the drawings, I have illustrated a combination fuel burner of the invention adapted for the simultaneous or independent burning of natural gas, by-product gas such as propane, and oil, in a furnace 10. The fuel burner generally consists of a fluent fuel discharge means 20, in association with a pair of gas rings 40 and 50, arranged to independently discharge a corresponding fuel stream through a burner port 12 in a furnace refractory wall 14 and into a furnace 10. Combustion supporting air for all three fuel discharge means is supplied through an air register arrangement 60 in a manner to be described more fully hereinafter.

The complete burner unit is mounted adjacent. the burner port 12 so as to extend through a combustion air passage 11. Thelair passage 11 is defined by the furnace wall 14 and a casing 13, which is spaced from, and parallel to, said furnace wall. An outside burner cover plate15, comprising a removable central portion 15a and a. removable outer portion 15b, is fastenedby means of bolts, attached around the, peripheryof a hole in the casing 13. The cover 15 partly supports the outside end 2,822,864 Patented F eb. 11, 195.8

of. the burner unit from the casing 13. A cylindrical tube 17, which extends through the central portion 15a of the cover plate, and is axiallyaligned with the center of the burner port, provides a means for axially positioning the fluent fuel discharge means 20.

In the embodiment shown, the fluent fuel discharge means 20 is a steam-atomizing type of oil atomizer similar to that shown in Patent 2,613,112.. It includes an elongated, cylindrical distance piece 21, which extends through the tube 17, and may be adjustably positioned in an axial direction relative to the furnace 16. by sliding it in the tube 17, using a handle 22. attached thereto for that purpose. It is held in an adjusted position by a clamp 18. arranged on the portion of the tube 17 projecting outside. the cover plate. The internal parts of the atomizer are more fully described in Patent 2,613,112 referred to above. The atomizer is arranged to spray a liquid fuel in the form of a fine liquid spray through a spray nozzle 23 located on the furnace end of the atomizer. Fuel, and steam to atomize the fuel, are delivered to the atomizer through, conduits 24 which are supported from. the opposite casing endof the distance piece. The conduits 24 are connected to internal passages inside the distance piece through a removable coupling 25 which is clamped in position on the external end of the atomizer by a T-handle clamp 26. An air impeller 27 of frusto-conical shape, provided with deflector vanes 28 to give a swirling motion to the air passing therethrough, is mounted on the distance piece at the furnace end thereof.

The air passage 11 between the furnace walls and the casing is normally-supplied with air under pressure, and the register 60 separates this passage from the burner port 12. The register is generally of cylindrical shape, and arranged coaxially with the oil atomizer. The register includes: a cylindrical section 61 axially aligned with the atomizer and adjacent to the cover plate 15a, circular plates 62 and 63 having hollow circular central portions defining a larger cylindrical air door portion 64, and a 'frusto-conical furnace end 65. The air door section 64 :is made up of a series of curved pivoted. doors, or dampers, 66 for controlling the passage of air from the .air passage 11 to the furnace port. The degree of opening a of doors 66 is adjusted by suitable. operating means including a hand crank 67 which extends, through the outer portion of burner cover plate 15b.

In accordance with the invention, ,two gas rings are positioned concentrically in the port 12. in proximity to the discharge end of the centrally positionedoil' atomizer. The gas rings are of torus form and include. a large ring; :50 arranged in the port 12 on the furnace; side thereof, and a smaller ring 40 coaxially juxtaposed to the large ring on the casing side of the port 12. The rings are: arranged with their walls in contact with each other to insure that gas flowing through onlyone ring, when in. operation, will act to cool the walls of the ringnot in use- 'The large ring 50 is connected to a gas supply conduit 51 which extends into the refractory-wall 14 subj'a cen't the ring. Specially shaped refractory bricks 52 fit around the outside curved portion of the large ring and form a generally smooth, substantially frusto-conicalsurface in f the port 12 leading from. the inside surface of the large ring to the furnace 16. These bricks act to, shield the rings from the hot gases normally in thefurnaceandal'soaid in supporting. and, positioning the... ring in theport. The conduit, 51 is connected. by a, bolt 53 to agas; supply pipe line 54 which extends upwardly to a position above the gas rings and thence horizontallythrough the casing 13 to agas supply. valve 55. ,The small ring 40 is connected through a conduit 41 to a gas supply pipe line 42, which extends upwardly and outwardly, then downwardly to a position below the rings, and thence horizontally through the casing 13 to a gas supply valve 43. The gas piping aids in supporting and positioning each ring in the port 12.

The gas rings of r the illustrated embodiment are .of

different diameters. The casing-side ring 40 has a smaller internal diameter than the furnace-side ring 50 in order to handle a by-product gas which is available in smaller and/or intermittent quantities or flow'rates. However, rings of the same 'sizelcould be used, depending on available gas flow rates. The inner circumferences of the rings are tangent to 'a' common cylinder also tangent to the furnace end of the frusto-conicalvsection 65 of the register 60. The large ring is shielded from the furnace by the refractory bricks 52, and in turn acts to shield the smaller ring.

Projecting radially from the inside surfaces of the rings are a plurality of tubular gas nozzles, or outlets,

designated 44 on the small ring and 56, 57 and 58 on the large ring. In the embodiment shown, the smaller ring 40 has a single row of gas nozzles 44 comprising a total of 30 cylinders of, for example, one eighth inch diameter and two inches long, equally spaced around the inside periphery of the ring and connected thereinto. The larger ring 50 has three rows of nozzles comprising, in a typical example: an inner row of fourteen cylindrical nozzles 56 one inch long and one eighth inch diameter, equally spaced around the inner periphery of the ring and connected thereinto, eighty-four one-eighth inch diameter equally spaced nozzle holes 57 drilled into ring 50 in the same row as the cylindrical nozzles 56, and an outer row of nozzles 58, of ninety-eight one-eighth inch diameter equally spaced holes drilled into said ring at about 30 from the inner row toward the furnace side.

In accordance with the invention, the nozzles 44 on the smaller ring are of a greater radial length, i. e. they extend closer to the center line of the port 12 than the nozzle cylinders 56, or nozzle holes 57 and 58 on the larger, furnace-side ring. With this expedient, gas exit- 7 ing from the upstream nozzles 44 is blown clear of the downstream nozzles, and will not impinge thereon. In addition, the gas which is discharged from these longer nozzles is away from the ring surface so that the gas therefrom is discharged directly into the main air stream, at which point the gas is subjected to eddying of the whirling air exiting from the register cone 65. For this reason, the smaller ring is particularly adaptable for the burning of a low quality gas, or for the burning of gas which is supplied intermittently or irregularly. In the event that the ignition temperature of such a gas cannot be maintained continually when burned alone, it may be burned along with either of the other fuel discharge means. When thus arranged, the gas exiting from this ring will be blown out past the larger ring, or into the central burner flame, where it can be ignited and burned from the gas being burned at the large ring, or the oil, or other fuel, from the central fuel discharge means.

In operation, all of the combustion air supply for any one or all of the burners passes through the air doors 66 and is controlled by a single air door crank 67. Air entering through the doors 66 of the register is given a whirling motion as it passes each of the individual fuel discharge means and exits through the port 12. Fuel may'be discharged into the furnace from the central atomizer, or any one of the gas port rings, or any combination of one to three of these means. With the invention it is also possible to discharge a sludge, or any other liquid fuel which is diflicult to burn, through the central atomizerand still maintain ignition by burning gas from either offthe sets of gas nozzles in effective proxtothe atomizedliquid fuel. In a similar manner,

a gas of lo'w'heating value or intermittent supply, may be introduced into the furnace port from one of the gas rings such as the smaller ring which is upstream in the combustion air supply and most remote from the furnace, whereby the heat from the combustion of fuel from the larger ring, or from the central atomizer may be used to maintain an adequate ignition temperature in the proximity of the ring burning the low quality fuel to keep it burning.

The expedient of arranging the burners for three fuels in one unit not only provides a compact, relatively low cost burner assembly, with a minimum of fittings and connections, necessitating only one air supply and control therefor, and one furnace opening instead of three; but also has the advantage of improved combustion of each of the fuels and the provision of a means to burn waste gases which would otherwise be unusable. With the invention, only one burner lighting means is necessary for the whole unit, and any one of the fuels that are used as a standby are instantly serviceable, when heating requirements change, by lighting one fuel from another that is already burning. The burner unit provides a great saving in expense in respect to furnace arrangement and total parts, and, inasmuch as combustion air regulation is achieved for'all three fuel discharge means by a single control lever, it is simple to operate and to control.

While in accordance with the provisions of the statutes there is illustrated and described herein the best form of the invention, those skilled in the art will understand that changes may be made in the form of the apparatus without departing from the spirit of the invention covered by the claims, and that certain features of the invention may sometimes be used to advantage without a corresponding use of other features.

I claim:

1. In combination, a furnace wall having a circular burner port therein, a fuel burner assembly comprising a first gas burner ring positioned in said burner port, a first combustible gas supply means including a flow control supplying gas to said first burner ring, a second gas burner ring arranged in said burner port axially adjacent and positioned to be shielded from the furnace radiation by said first burnerring, a second combustible gas supply means separate from said first combustible gas supply means and including a flow control supplying gas to said second burner ring of a different composition-than the gas supplied to said first burner ring, a plurality of circumferentially spaced gas discharge nozzles in each of said rings, and common air supply means for both of said rings.

2. In combination, a furnace wall having a circular burner port therein, a fuel burner assembly comprising a first gas burner ring positioned in said burner port, a first combustible gas supply means including a flow control supplying gas to said first ring, a second gas burner ring arranged in said burner port axially adjacent and positioned to be shielded from the furnace radiation by said first burner ring, a second combustible gas supply means separate from said first combustible gas supply means and including a flow control supplying gas to said second burner ring of a different composition than the gas supplied to said first burner ring, a plurality of circumferentially spaced tubular gas discharge nozzles in each of said rings with the tubular nozzles of said first ring arranged to extend closer to the axial centerline of said port than the tubular nozzles of said second ring, and common air supply means for both of said rings.

3. In combination, a furnace wall having a circular burner port therein, a fuel burner assembly comprising a first gas burner ring positioned in said burner port, a first combustible gas supply means including a flow control supplying gas to said first burner ring, a second gas burner ring arranged in said burner port axially adjacent and positioned to be shielded from the furnace radiation by said first burner ring, a second combustible gas supply 5 means separate from said first combustible gas supply means and including a flow control supplying gas to said second burner ring of a different composition than the gas supplied to said first burner ring, a plurality of circumferentially spaced tubular gas discharge nozzles in each of said rings with the tubular nozzles of said first ring arranged to extend closer to the axial centerline of said port than the tubular nozzles of said second ring, a fluid fuel discharge means centrally aligned in said burner port and ring burners and arranged to discharge a combustible immediately adjacent said ring burners,

6 and common air supply means for both of said rings and fluid fuel means.

References Cited in the file of this patent UNITED STATES PATENTS 1,791,565 Killarn Feb. 10, 1931 1,801,431 Irish Apr. 21, 1931 1,887,040 Ragon Nov. 8, 1932 1,927,299 Sanders Sept. 19, 1933 1,951,379 Voorheis Mar. 20, 1934 2,679,833 Andrews et al. June 1, 1954 

